Multi-contact switching device



y 1963 H. v. ALEXANDERSSON ET AL 3,096,422

MULTI-CONTACT SWITCHING DEVICE Filed Jan. 29. 1960 2 Sheets-Sheet 1f/VVE/V 7-0195 1977-0 RN r5 July 2, 1963 Filed Jan. 29, 1960 H. V.ALEXANDERSSON ET AL MULTI-CONTACT SWITCHING DEVICE 2 Sheets-Sheet 2 171vI/EA/rORs Hm M 3,096,422 MULTI-CUNTACT SWITCHlNG DEVICE Harald ValdemarAlexandersson, Lidingo, and Anne Kurt Dietsch, Enskede, Sweden,assignors to Telefonaktiebolaget L. M. Ericsson, Stockholm, Sweden, acorporation of Sweden Filed Jan. 29, 1960, Ser. No. 5,442 Claimspriority, application Sweden Feb. 19, 1959 Claims. ((31. 200-166) Incontact spring multiples built of plate springs in several parallelpiles or groups of springs lying above each other a lifting rib isnormally used as an actuating member for the springs in a group, saidlifting rib is in most cases cut out from a plate of paper laminate. Thelifting rib is generally placed inside and right through the springs,which are actuated by teeth in one edge of the lifting rib. If wiresprings or similar springs are used the lifting rib must, of course, liemainly outside the contact springs. In the case a contact springmultiple constructed of wires is wanted, for example for cross barswitches, and it is desirable to have small dimensions sideways of thewire in order to construct a very compact multiple, the problem arisesthat the lifting ribs take too much space if they are constructed intraditional manner. While it is possible to arrange the lifting ribs intwo or more rows displaced in relation to each other, when thisarrangement is used the working point on the contact springs will beplaced differently, the bending will be different and the contactpressures will differ too much from each other. Lifting ribs providedwith teeth on their broad side are also a possibility. However, in suchcase the production becomes expensive, as ordinary cutting out of therib is not possible.

A practical and cheap solution of the problem is obtained if the presentinvention is used. This invention is mainly characterized in that thelifting ribs have a breadth which is bigger than the distance sidewaysbetween the contact wires. Thus, the cross direction of the lifting ribsforms an angle less than 90 with respect to the longitudinal directionof the contact wires.

The invention will be further described with reference to theaccompanying drawings. FIG. 1 shows a side view of a Wire spring set.FIG. 2 shows four groups of a multiple seen from above. FIG. 3 shows inperspective and in large scale three groups in a multiple seen from infront. FIG. 4 is an enlarged picture of a lifting rib.

In the drawing only the details of a multiple necessary for explainingthe invention are included, and this multiple comprises a number ofparallel lying spring sets of the kind shown in FIG. 1. Each groupincludes a number of wire springs 3 lying above each other and fastenedin a normal way at their rear left ends. The front right ends of thewires are lifted upwards from the position of rest shown in the drawingby a lifting rib or bar 1 for each group, said lifting rib beingactuate-d in a known way which is not shown.

The lifting rib 1 is provided with a number of oval holes 2 for thecontact wires 3. The holes are provided with a convex edge 4 upon whichthe contact wires rest. 6

The holes are suitably formed, at least on one side, with a greaterwidth than the remainder of the holes to enable the lifting rib to bethreaded on the contact wires. The contact wires are provided withapplied tubes 5 or sleeves of contact material at their front end. Whenthe contact wires are actuated by the lifting ribs, these tubes makecontact with wires 6, which are disposed in a stand 7 of insulatingmaterial and extend transverse of the contact wires 3. The distancesideways between the contact wires 3 in the different groups is smallerthan the width of conventional lifting ribs, so that the ribs can not beplaced in a row with their cross direction perpendicular to the 3,096,422 Patented July 2, 1963 longitudinal direction of the contactwires. According to the invention the lifting ribs are placed so thattheir cross direction forms an angle less than with the longitudinaldirection of the contact wires 3. The ribs are guided in their positionby diagonal holes in an upper and a lower guiding plate 8 respectively9. The holes 2 in the ribs are dimensioined so that the contact wiresobtain a relatively good side guiding. When the ribs are lifted, theribs are turned upon contact of the Wires with the lower limiting edgesof the holes 2 owing to the inclined position of the ribs towards thecontact wires. This turning moment is unfavorable, since extra frictioncan appear owing to this. However, these frictions can be kept down atsafe values, by forming the holes in the lifting ribs with the saidconvex form. It would, of course, be possible to provide the liftingribs with teeth instead of holes in one edge, but then the mechanicalstability will be smaller.

With the spring sets of the described wire spring type there is a needto center the wire springs 3 in their rest position. The wire springscannot be directed so precisely that all the wires in a group get intoexactly the same position below each other. This is especially true whenthey are actuated by diagonal ribs. The holes in the ribs aredimensioned so that relatively good side guiding is obtained aspreviously mentioned, but still derivations in guiding appear at thefront ends of the contact wires. As shown in embodiment of FIG. 3 it isnecessary that the contact sleeves 5 are positioned in relation to thesurrounding insulating material of the stand '7 so that no wear and tearappears when the contact wires move upwards and downwards. If a wirespring is free in its inactive rest position, i.e. when it lies againstthe lower part of the slots for the contact wires in the stand 7, itwill take a position so that the contact sleeve 5 at its movementupwards will drag along the vertical side edges of the slots in theinsulating material. This causes debris of insulatingand contactmaterial to remain both on the contact sleeves and on the limitingsurfaces of the slots in the stand 7 at such places where it mayadversely affect the contact make and break qualities. Thisinconvenience can be prevented if the side edges of the slots are drawncloser to each other downwards in such a manner that the wires arecentered in predetermined rest positions. :11? a wire should have a sidepressure, it is taken up by the vertical limiting surfaces, until thewire again is brought upwards by the lifting rib.

We claim:

1. A. multi-contact switching device comprising a plurality ofsubstantially straight contact springs fixedly mounted at one end andgrouped spaced apart in vertical and transverse rows, a plurality ofstationary contacts each engageable with one of said contact springs atthe free end thereof, and a lengthwise displaceable vertically disposedinsulation lifting bar for each vertical row of contact springs, saidbars being aligned in a row transverse of said contact springs, each ofsaid bars contacting with all the contact springs in the respectivevertical row to move said springs into and out of engagement with therespective stationary contacts by lengthwise displacement of the bars,said bars having a width greater than the transverse spacing between twoadjacent vertical rows of springs and being positioned to define anangle of less than 90 with said contact springs whereby upondisplacement of the bars into the contact-making position, a uniformcontact pressure is exerted at all the stationary contacts in therespective vertical row.

2. A switching device according to claim 1 wherein each of said liftingbars has several vertically spaced holes therethrough one for eachcontact spring in the respective vertical row, the transverse width ofsaid holes permitting passages of the springs during assembly of thedevice and placement of the bars at a slant in reference to the lengthof the springs.

3. A switching device according to claim 2 wherein a contact sleeve issecured upon the free end of each contact spring, each of said holes inthe bars having a portion widened to permit passage of the respectivecontact sleeve. 7

4. A switching device according to claim 2 wherein the lower edge ofeach hole is convexly curved in reference to the respective contactspring extending through the hole, the apex of the convexly curved edgesupporting the respective spring to guide the same during movementwithin the hole.

5. A switching device according to claim 2 wherein said holes are formedwith end portions that are substantially wider in vertical directionthan the central portion 4 of the holes, said end portions guiding saidsprings in said holes when the springs are moved into the contact-makingpositions by said lifting bars.

References Cited in the file of this patent UNITED STATES PATENTS1,647,792 Gent NOV. 1, 1927 2,638,514 Martin May 12, 1953 2,846,547Pettet Aug. 5, 1958 2,902,549 Bernstein Sept. 1, 1959 FOREIGN PATENTS58,924 Denmark July 28, 1941 62,914 Norway Oct. 7, 1940 526,371 BelgiumFeb. 27, 1954 1,025,046 Germany Feb. 27, 1958

1. A MULTI-CONTACT SWITCHING DEVICE COMPRISING A PLURALITY OFSUBSTANTIALLY STRAIGHT CONTACT SPRINGS FIXEDLY MOUNTED AT ONE END ANDGROUPED SPACED APART IN VERTICAL AND TRANSVERSE ROWS, A PLURALITY OFSTATIONARY CONTACTS EACH ENGAGEABLE WITH ONE OF SAID CONTACT SPRINGS ATTHE FREE END THEREOF, AND LENGTHWISE DISPLACEABLE VERTICALLY DISPOSEDINSULTION LIFTING BAR FOR EACH VERTICAL ROW OF CONTACT SPRINGS, SAIDBARS BEING ALIGNED IN A ROW TRANSVERSE OF SAID CONTACT SPRING, EACH OFSAID BARS CONTACTING WITH ALL THE CONTACT SPRINGS IN THE RESPECTIVEVERTICAL ROW TO MOVE SAID SPRINGS INTO AND OUT OF ENGAGEMENT WITH THERESPECTIVE STATIONARY CONTACTS BY LENGTHWISE DISPLACEMENT OF THE BARS,SAID BARS HAVING A WIDTH GREATER THAN TH TRANSVERSE SPACING BETWEEN TWOADJACENT VERTICAL ROWS OF SPRINGS AND BEING POSITIONED TO DEFINE ANANGLE OF LESS THAN 90* WITH SAID CONTACT SPRINGS WHEREBY UPONDISPLACEMENT OF THE BARS INTO THE CONTACT-MAKING POSITION, A UNIFORMCONTACT PRESSURE IS EXERTED AT ALL THE STATIONARY CONTACTS IN THERESPECTIVE VERTICAL ROW.